Tape winding method and device, and tape winding body

ABSTRACT

In the tape winding method and the tape winding device according to the present invention, the first to the fourth rollers are provided, and the position and the like of the tape are restrained by the rollers. Therefore, the tape with the curvature amount of 6 mm or less per the tape length of 1 m can be wound up at a high speed and can be made favorable in the winding shape. Moreover, the position of the fourth roller is controlled so as to prevent contact of the tape to the shaft part surface of the fourth roller, and even if the curvature of the tape is large, the position of the tape in the width direction to the winding hub by the fourth roller can be reliably performed, as a result of which, winding of the tape which can provide a favorable winding shape is made possible.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tape winding method and device and a tape winding body, and particularly relates to a tape winding method and device and a tape winding body capable of winding a magnetic tape at high speed and making a winding shape favorable.

2. Description of the Related Art

Various kinds of so-called pancakes (tape winding bodies each with a magnetic tape wound around a winding hub) which are used for cassette tapes and video tapes, and also used for data backup for computers are manufactured by drawing out a wide, belt-shape raw magnetic tape wound in a roll shape from a feeding side and cutting the raw magnetic tape into a plurality of narrow magnetic tapes while conveying the raw magnetic tape, and winding the magnetic tapes around flangeless hubs at a winding side.

As such pancakes, it is desired that their wound magnetic tapes be as long as possible in the respect of productivity, and from the same viewpoint, a winding method at the winding speed as fast as possible is desired.

As a magnetic tape winding method and device for manufacturing a pancake to cope with such a challenge, there are various conventionally known methods which make high-speed winding possible.

For example, according to Japanese Patent Application Publication No. 62-31645, there is proposed a construction of winding a magnetic tape by combining a position restraining roller just before a pancake, and an edge restraining roller and a pressing roller which are in contact with the pancake. According to Japanese Patent Application Publication No. 5-159284, there is proposed a construction which decreases layer down and winding disarrangement of the magnetic tape by three or more of restraining rollers. According to Japanese Patent Application Publication No. 7-296556, there is proposed a construction which makes high-speed winding possible by a head section including a main touch roller in contact with pancake and a guide roller provided just before the main touch roller.

Incidentally, in recent years, as a purpose of using a magnetic tape, use for magnetic recording medium of a backup computer becomes a main stream. When using the magnetic tape in such a backup computer, a servo signal is recorded on a surface of the magnetic tape. On this occasion, the winding shape of the pancake before the servo signal is written becomes important. Namely, if the winding shape is unfavorable, the servo signal cannot be accurately recorded, which becomes the disadvantage in quality. If the winding shape is unfavorable, an edge portion of the magnetic tape is easily damaged during storage, transportation and other circumstances.

Many of the magnetic tapes in recent years are thin and smooth, and become more difficult to wind as compared with the conventional magnetic tapes. As a result, the above-described defects become the problems. FIGS. 14A, 14B, 14C and 14D are conceptual views showing each example in which the winding shape of a magnetic tape 1 is unfavorable. In the drawings, sections of pancakes 3 are shown. The pancake 3 is formed by winding the magnetic tape 1 around a winding hub 2. In each of the drawings, the magnetic tape 1 is wound around the hub 2 by being guided by guide rollers 4 and 4.

FIGS. 14A and 14B show winding defects in which the magnetic tape 1 cannot be restrained with the flanges of the guide rollers 4 at the time of start. Of the two, FIG. 14A is the state 5 in which the magnetic tape 1 protrudes from the flanges of the guide rollers 4 when it is wound on the winding hub 2, which is also called a protruding defect at the time of increasing speed. FIG. 14B is the state 6 in which the magnetic tape 1 protrudes out of the flange from the state in which it is inside the flange of the guide roller 4.

FIG. 14C is a defect called “irregular winding” among the defections called “winging disarrangement”, and is the state 7 in which an end surface of the magnetic tape 1 is not uniform. The magnetic tape 1 is wound up in the state in which the end surface of the magnetic tape 1 is not uniform, thereby causing another “winding disarrangement” called “end surface abrasion” in which the end surface of the magnetic tape 1 is rubbed by the flange of the guide roller 4 and damaged.

FIG. 14D is the defect called “protrusion”, which is the state 8 in which the magnetic tape 1 protrudes out of the flange from the state in which the magnetic tape 1 is inside the flange of the guide roller 4, in the state in which the magnetic tape 1 is wound around the winding hub 2 by the considerable length.

Though the above-described defects become the problem as above, these defects cannot be eliminated by the conventional technique in the present situation. In the three references mentioned above, the sufficient measures against the above-described defects are not taken because the fine positional adjustment function of the winding hub 2 and the guide roller 4 is not included. Especially when the curve of the magnetic tape 1 is large as shown in the below, there arises the trouble that the magnetic tape 1 is displaced in the width direction and is removed from the winding hub 2.

The magnetic tape 1 is manufactured by being cut into a plurality of tapes from the wide raw magnetic tape. Generally, on the raw magnetic tape, a magnetic layer is formed to be thick in the central part in the width direction of the raw magnetic tape and thin at both end portions in the width direction. FIGS. 15A, 15B and 15C are conceptual diagrams showing the thickness distribution and the like of the raw magnetic tape, and FIG. 15A is a graph showing the result of measuring the surface profile in the width direction in the state in which the raw magnetic tape 20 is wound around the hub (winding core) in the roll shape. As in the graph, the crowing amount is as high as 874 μm in the raw magnetic tape of a predetermined width. Especially extreme portions are both end portions in the width direction in the raw material roll state. For example, the difference in the thickness (inclined thickness amount) between both sides with the width of 12.65 mm is 52 μm in the circle at the right end portion, and 70 μm in the circle at the left end portion.

Accordingly, even if such raw magnetic tape cut into the magnetic tapes 1 of the width of 12.65 mm, for example, the thickness distribution in the width direction remains. Thus, the magnetic tape 1 obtained from raw magnetic tape 20 at the above-described portions (both end portions in the width direction) is in the curved shape as shown in FIG. 15B at the left end portion and as shown in FIG. 15C at the right end portion. The degree of the curved shape is indicated as the value set as a curvature amount Δ with respect to the length L.

FIGS. 16A, 16B and 16C are conceptual views explaining the state in which the magnetic tape 1 having a curvature is wound up. FIG. 16A is a predetermined length of the magnetic tape 1 having a curvature shown in FIG. 15B, the length of the left side edge is L1, and the length of the right side edge is L2. FIG. 16B is the state in which a tension force is applied to the magnetic tape 1 and the curvature is eliminated, and the length of the left and right side edges are both substantially L2. In this case, it is estimated that the internal stresses corresponding to the arrow lengths in FIG. 16B occur to the left and right side edges of the magnetic tape 1.

FIG. 16C shows the state in which the magnetic tape 1 is wound around the winding hub 2. In this case, winding of the magnetic tape 1 is performed in the state shown in FIG. 16B, but the internal stresses at the left and right side edges of the magnetic tape 1 differ, and therefore the force to displace in the direction of the arrow shown in FIG. 16C occurs so as to relieve the internal stresses. Accordingly, when the magnetic tape 1 having a curvature is wound around the winding hub 2, the protrusion in the width direction easily occurs.

SUMMARY OF THE INVENTION

The present invention is made in view of the above circumstances, and has its object to provide a tape winding method and device and a tape winding body capable of winding up a tape at high speed and making a winding shape favorable.

In order to attain the above-described object, the present invention provides, in a tape winding method for winding a tape around a winding hub, a tape winding method comprising the steps of placing an axis of the winding hub to be horizontal, restraining an entry direction of the tape into the winding hub by a first roller, which is provided at an upstream side in a tape traveling direction of the winding hub so that the axis of the winding hub and an axis of the first roller are substantially parallel with each other, restraining a position of the tape in a width direction by a second roller which contacts a tape roll formed by the tape being wound around the winding hub, and is provided so that the axis of the winding hub and an axis of the second roller are substantially parallel with each other, pressing the tape at an outermost periphery of the tape roll by a third roller provided so that the axis of the winding hub and an axis of the third roller are substantially parallel with each other, restraining a position of the tape in the width direction by a fourth roller with a flange which restrains the position of the tape in the width direction while contacting the tape roll, at a downstream side in a tape traveling direction of the third roller at the outermost periphery of the tape roll, and is provided so that the axis of the winding hub and an axis of the fourth roller are substantially parallel with each other, and winding the tape with a curvature amount of 6 mm or less per a tape length of 1 m around the winding hub, and a device used for the method.

According to the present invention, the first to the fourth rollers are provided, and the position and the like of the tape are restrained by these rollers. Therefore, the tape with the curvature amount of 6 mm or less per the tape length of 1 m can be wound up at a high speed into a favorable winding shape.

The present invention also provides, in a tape winding method for winding a tape around a winding hub, a tape winding method comprising the steps of placing an axis of the winding hub to be horizontal, restraining an entry direction of the tape into the winding hub by a first roller, which is provided at an upstream side in a tape traveling direction of the winding hub so that the axis of the winding hub and an axis of the first roller are substantially parallel with each other, restraining a position of the tape in the width direction by a second roller which contacts a tape roll formed by the tape being wound around the winding hub, and is provided so that the axis of the winding hub and an axis of the second roller are substantially parallel with each other, pressing the tape at an outermost periphery of the tape roll by a third roller provided so that the axis of the winding hub and an axis of the third roller are substantially parallel with each other, and controlling a distance of a fourth roller with respect to the tape roll so that a shaft part surface of the fourth roller does not contact the tape, in which the fourth roller is a roller which restrains the position of the tape in the width direction while contacting the tape roll at a downstream side in the tape traveling direction of the third roller at the outermost periphery of the tape roll, and is provided so that the axis of the winding hub and the axis of the fourth roller are substantially parallel with each other, and the fourth roller being constructed by a shaft part and flange parts disposed at both sides of the shaft part, having taper portions in which a space between the inner surfaces of the flange parts becomes larger toward an outer diameter direction from an inner diameter direction formed in the inner surfaces of the flange parts, and a device which is used in the method.

According to the present invention, the winding hub is provided so that the axis becomes horizontal, the first to the fourth rollers are provided so that the winding hub and the axes of the rollers are substantially parallel with each other, and thereby winding of the tape around the tape roll is restrained. In the construction in which the position of the tape in the width direction is restrained by the fourth roller provided at the downstream side of the third roller, the fourth roller is constructed by the shaft part and the flange parts disposed at both sides of the shaft part, and the distance of the fourth roller with respect to the tape roll is controlled to support the tape while preventing the contact of the tape to the shaft part surface. Thereby, even when the curvature of the tape is large, the positional restraint of the tape in the width direction to the winding hub by the fourth roller can be reliably performed, winding of the tape can be performed at a high speed, and the tape winding which can make a favorable winding shape becomes possible.

In the present invention, it is preferable that the surface roughness Ra of the inner surface of the flange part of the fourth roller is 0.15 μm or less. By providing the inner surface of such surface roughness, occurrence of a flaw of the tape is restrained, and as a result, the quality of the tape winding body can be improved.

In the present invention, it is preferable to set a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm. By using such a fourth roller, restraint of the position of the tape in the width direction to the winding hub can be reliably performed, and the occurrence of the flaw of the tape is restrained, as a result of which, the quality of the pancake can be improved.

As explained above, according to the present invention, the first to the fourth rollers are provided, and the position and the like of the tape are restrained by the rollers. Therefore, the tape with the curvature amount of 6 mm or less per the tape length of 1 m can be wound up at a high speed and can be made favorable in the winding shape.

According to the present invention, the position of the fourth roller is controlled so as to prevent contact of the tape to the shaft part surface of the fourth roller, and even if the curvature of the tape is large, the position of the tape in the width direction to the winding hub by the fourth roller can be reliably performed, as a result of which, winding of the tape which can provide a favorable winding shape is made possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual view showing a construction of a manufacturing apparatus of a pancake which is applied to the present invention;

FIG. 2 is a schematic diagram of a cutting device;

FIG. 3 is a schematic diagram of a winding device of a magnetic tape according to the present invention;

FIG. 4 is a side view showing a construction of a position restraining roller;

FIG. 5 is a side view showing a construction of an edge restraining roller;

FIG. 6 is a side view showing a construction of an auxiliary edge restraining roller;

FIG. 7 is a perspective view of a winding device of a magnetic tape;

FIG. 8 is a partially plan view of FIG. 3;

FIG. 9 is a left side view of FIG. 3;

FIG. 10 is a partially enlarged left side view of FIG. 3;

FIGS. 11A to 11C are partially enlarged side views each showing positional relationship of the auxiliary edge restraining roller and a tape roll;

FIG. 12 is a graph showing a result of Example 1;

FIG. 13 is a table showing a result of Example 2;

FIGS. 14A to 14D are sectional views of pancakes each showing a state of winding fault;

FIGS. 15A to 15C are conceptual views showing thickness distribution and the like of a raw magnetic tape; and

FIGS. 16A to 16C are conceptual views each explaining a state in which a magnetic tape having a curvature is wound up.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of a tape winding method and device and a pancake according to the present invention will be explained in detail concerning the case of winding up a magnetic tape with reference to the attached drawings, hereinafter. FIG. 1 is a conceptual view showing a construction of a manufacturing apparatus 10 of a pancake to which the present invention is applied, FIG. 2 is a side view of a cutting device 14, and FIG. 3 is a schematic diagram showing a magnetic tape winding device 15.

As shown in FIG. 1, the pancake manufacturing apparatus 10 is mainly constructed by a feeding device 11 which feeds a raw magnetic tape 20 wound in a roll shape, a cutting device 14 which cuts the wide belt-shaped raw magnetic tape 20 into a plurality of narrow magnetic tapes 1, and winding devices 15 which wind the magnetic tapes around the winding hubs 2.

The raw magnetic tape 20 wound in the roll shape is fitted onto a hub 12 (winding core) of the feeding device 11. The raw magnetic tape 20 is generally manufactured by forming a magnetic layer including ferromagnetic fine particles on a non-magnetic supporter by a coating method, a vacuum deposition method or the like, and performing orientation treatment, dry treatment, surface treatment and the like for the magnetic layer.

The cutting device 14 is the device which cuts the wide belt-shaped raw magnetic tape 20 into a plurality of magnetic tapes 1 by a pair of upper and lower rotary blades 30 and 32, and is constructed by a plurality of rotary lower blades 30 formed in the roller shape as receiving blades, and a plurality of thin disc-shaped rotary upper blades 32 which gives the shearing force to the raw magnetic tape 20 in the space from the rotary lower blades 30 to cut the raw magnetic tape 20 as shown in FIG. 2.

The rotary lower blade 30 is fitted and fixed onto a lower shaft 34 via a spacer 36, and the rotary upper blade 32 is fitted and fixed onto an upper shaft 38 parallel with the lower shaft 34 via a spacer 40. The rotary lower blade 30 and the rotary upper blade 32 are disposed so that blade edge portions of the rotary upper blade 32 and the rotary lower blade 30 overlap each other. The rotary upper blade 32 is biased to the right side in the axial direction in FIG. 2 by a spring not shown and is positioned in the state in which the blade edge portion of the rotary upper blade 32 abuts to the blade edge portion of the rotary lower blade 30.

The upper shaft 38 and the lower shaft 34 are respectively connected to motors 41 and 43 capable of freely changing the respective rotational speed, so that the circumferential speeds of the rotary upper blade 32 and the rotary lower blade 30 can be changed individually.

In FIG. 1, a plurality of guide rollers 22 which form a transfer path of the raw magnetic tape 20, and a grooved suction drum 24 which restrains the transfer speed of the raw magnetic tape 20 are provided between the feeding device 11 and the cutting device 14. The grooved suction drum 24 is connected to a motor (not shown) of which rotational speed is freely changeable, and can optionally change the transfer speed of the raw magnetic tape 20 by rotating with the raw magnetic tape 20 sucked on a peripheral surface of the grooved suction drum 24.

The rotational speed of a winding core 18 of the winding hub 2 in the winding device 15 is controlled with the circumferential speed of the grooved suction drum 24 as the reference. The device which restrains the transfer speed of the raw magnetic tape 20 is not limited to the grooved suction drum 24, but a pinch roller which nips and transfers the raw magnetic tape 20 can be used.

A tension roller 28 is provided between the cutting device 14 and each of the winding hubs 2, and the tension in the transfer direction of the raw magnetic tape 20 at the time of cutting is optionally adjusted.

As shown in FIG. 3, the winding device 15 includes the winding hub 2, a position restraining roller 50 which is a first roller, an edge restraining roller 52 which is a second roller, a pressing roller 54 which is a third roller and an auxiliary edge restraining roller 56 which is a fourth roller.

The position restraining roller 50 is rotatably supported in the vicinity of a base end portion (left end portion in FIG. 3) of a lower arm 60 via a bearing 51. The edge restraining roller 52 and the pressing roller 54 are rotatably supported via a support plate 58 provided in the vicinity of a tip end portion (right end portion in FIG. 3) of the first arm 60. The auxiliary edge restraining roller 56 is rotatably supported in the vicinity of a tip end portion (left end portion in FIG. 3) of a support arm 62.

The winding hub 2 is provided at an apparatus body (building frame) not shown so that the axis is horizontal, and is rotationally driven in the counterclockwise direction as shown by the arrow. A tape roll 1′ is formed by winding the magnetic tape 1 around this winding hub 2. The tape roll 1′ with the magnetic tape 1 of the predetermined length wound around therearound becomes the pancake as the product.

The position restraining roller 50 which is the first roller is a flanged roller provided at the lower arm 60 at the upstream side in the tape traveling direction of the winding hub 2 so that the axis of the roller 50 is substantially parallel with the axis of the winding hub 2. The shape of the position restraining roller 50 is the roller with flanges 50B, and a surface of a roller 50A is formed by being crowned as shown in FIG. 4. The position restraining roller 50 is a solid product of stainless steel. The width of the roller 50A is formed to be substantially the same as the width of the magnetic tape 1. The flanges 50B and 50B have taper surfaces 50C and 50C inclined so that the space is larger toward the outer diameter portion from the inner diameter portion in the inner surface. This position restraining roller 50 restrains the entry direction of the magnetic tape 1 to the tape roll 1′.

The edge restraining roller 52 which is the second roller is the flanged roller which contacts the tape roll 1′ and is provided at the lower arm 60 so that the axis of the roller 52 is substantially parallel with the axis of the winding hub 2. FIG. 5 is a side view of the edge restraining roller 52. Flanges 52B and 52B are provided at both sides of a cylindrical roller 52A, and the roller 52A and the flanges 52B and 52B are connected via roller bearings 52D and 52D placed inside the roller 52A. Accordingly, the flanges 52B and 52B are rotatable with respect to the roller 52A.

The width of the roller 52A is formed to be a little smaller than the width of the magnetic tape 1. The roller 52A is formed of polyacetal, but may be formed of various kinds of resins other than polyacetal, for example, various kinds of engineering plastics. An inner surface of the flange 52B is formed to be taper surfaces 52C and 52C which incline so that a space becomes larger from an inner diameter portion which is the same as the outer diameter of the roller 52A to an outer diameter portion. The flange 52B is formed of stainless steel. It is preferable that surface roughness Ra of the taper surface 52C of the flange 52B is 0.15 μm or less. By providing such a smooth taper surface 52C, a defect can be prevented from occurring to an edge portion of the magnetic tape 1.

The edge restraining roller 52 restrains the position of the magnetic tape 1 in the width direction. Namely, the edge of the magnetic tape 1 abuts to the taper surface 52C, and thereby the position of the magnetic tape 1 in the width direction is restrained. In order to make the winding shape favorable by favorably restraining the position of the magnetic tape 1 in the width direction, it is preferable to set an inclination angle θc of the taper surface 52C within the range of 2 degrees to 15 degrees. It is also preferable to set the width of the roller 52A in the range of 95% to 99% of the width of the magnetic tape 1.

The pressing roller 54 which is the third roller is a columnar roller which presses the magnetic tape 1 at an outermost periphery of the tape roll 1′ and is provided at the lower arm 60 so that the axis of the roller 54 is substantially parallel with the winding hub 2. The pressing roller 54 is formed of urethane rubber, but may be formed of various kinds of synthetic rubber other than urethane rubber, such as, for example, silicon rubber, fluororubber, and chloroprene rubber. The pressing roller 54 is provided to push out air between the magnetic tape 1 and the tape roll 1′ by pressing the magnetic tape 1 and make the winding shape favorable. It is preferable that the width of the pressing roller 54 is a little smaller than the width of the magnetic tape 1. If the width of the pressing roller 54 is larger than the width of the magnetic tape 1, the surface of the pressing roller 54 is deformed into a recessed shape, and tends to cause a winding defect of the magnetic tape 1.

The edge restraining roller 52 and the pressing roller 54 are rotatably supported at the support plate 58. The support plate 58 is rotatably supported at the lower arm 60 with a support point 60A provided in the vicinity of the tip end portion of the lower arm 60 as a center.

The lower arm 60 is rotatably supported at the apparatus body (building frame) not shown with a support point 60B provided at the base end portion as a center. The lower arm 60 is biased to the tape roll 1′ side (in the counterclockwise direction) by a biasing device 61 constituted of a spring or the like. Thereby, the edge restraining roller 52 and the pressing roller 54 are pressed to the tape roll 1′ with predetermined pressure. It is preferable to set this pressing force at a predetermined force by which the edge restraining roller 52 and the pressing roller 54 are prevented from being separated from the tape roll 1′ by the rotation of the tape roll 1′. This pressing force may take an appropriate value in accordance with the width of the magnetic tape 1, the rotational frequency of the tape roll 1′, the quality of the material of the magnetic tape 1 and the like. As the biasing device 61, a known device such as an air cylinder can be adopted.

The auxiliary edge restraining roller 56 which is the fourth roller is provided at the opposite side from the edge restraining roller 52 and the pressing roller 54 with the tape roll 1′ therebetween. Namely, in the downstream side of the pressing roller 54 in the outermost periphery of the tape roll 1′, the auxiliary edge restraining roller 56 is provided so that the auxiliary edge restraining roller 56 is in contact with the tape roll 1′ and an axis of the auxiliary edge restraining roller 56 is substantially parallel with that of the winding hub 2.

FIG. 6 is a side view of the auxiliary edge restraining roller 56. In this auxiliary edge restraining roller 56, flanges 56B and 56B are provided at both sides of a cylindrical roller 56A, and the roller 56A and the flanges 56B and 56B are connected via roller bearings 56E and 56E placed inside the roller 56A. Accordingly, the flanges 56B and 56B are rotatable with respect to the roller 56A.

Since the auxiliary edge restraining roller 56 supports the tape roll 1′ and gently restrains the width of the tape roll 1′ with a predetermined looseness (gap, play), it is preferable to set the width of the roller 56A to be a little larger than the width of the magnetic tape 1. The roller 56A is formed of polyacetal, but it may be formed of various kinds of resins other than polyacetal, for example, various kinds of engineering plastics. The inner surface of the flange 56B is formed to be straight inner side surfaces 56D and 56D, and the outer diameter side from the inner side surfaces 56D and 56D is formed to be taper surfaces 56C and 56C which are inclined so that the space is larger toward the outer diameter part. The flange 56B is formed of stainless steel. As shown in FIG. 3, the auxiliary edge restraining roller 56 is rotatably supported at the support arm 62 with a support point 62A provided in the vicinity of the tip end portion of the support arm 62 as a center.

The support arm 62 is rotatably supported in a substantially horizontal direction by the upper arm 66 via a roller bearing which is a rotational support point 64, in a base end portion 62B. Further, the upper arm 66 is rotatably supported at the apparatus body (building frame) not shown in a substantially perpendicular direction in a base end portion 66A. The upper arm 66 is biased to the tape roll 1′ side (in the counterclockwise direction) by a biasing device 66B. Thereby, the auxiliary edge restraining roller 56 is pressed to the tape roll 1′ at predetermined pressure.

As the biasing device 66B, the combination of a ball screw 70 and a servo motor 72 is adopted. The servo motor 72 is rotatably supported at the building frame, and a screw portion 70A of the ball screw 70 is fixed to the rotary shaft of the servo motor 72. A ball head 70B (corresponding to a nut portion) of the ball screw 70 is firmly fixed to the upper arm 66. When the servo motor 72 is rotationally driven in this state, the ball head 70B moves in the substantially vertical direction, and the upper arm 66 rotates in the substantially vertical direction. The details of the positional control of the upper arm 66 by this biasing device 66B will be described later.

As the biasing device 66B, a known device such as a coil spring can be adopted other than the above. The pressing force by the auxiliary edge restraining roller 56 can take an appropriate value in accordance with the width of the magnetic tape 1, the rotational frequency of the tape roll 1′, the quality of material of the magnetic tape 1 and the like as in the lower arm 60, but it is preferable that the pressing force (touch pressure) at which the auxiliary edge restraining roller 56 presses the tape roll 1′ is adjustable to be variable in the range of 0.2 to 2.0 N.

Next, the function of the auxiliary edge restraining roller 56 will be explained. As explained by FIG. 15 and FIG. 16, when the magnetic tape 1 having a curvature is wound around the tape roll 1′ (winding hub 2), protrusion in the width direction easily occurs. The auxiliary edge restraining roller 56 is provided to prevent such protrusion in the width direction.

FIG. 7 is a perspective view of the magnetic tape winding device 15. In FIG. 7, the entry direction of the magnetic tape 1 to the tape roll 1′ is restrained by the position restraining roller 50, the position of the magnetic tape 1 in the width direction is restrained by the edge restraining roller 52, and the air between the magnetic tape 1 and the tape roll 1′ is pushed out by the pressing roller 54, whereby the winding shape is favorably restrained. However, in the case of the magnetic tape 1 with a large curvature, so-called protrusion D occurs, which is the magnetic tape 1 displacing in the width direction from the tape roll 1′ at the downstream of the pressing roller 54. In this case, the width of the tape roll 1′ is also restrained by the auxiliary edge restraining roller 56, and the protrusion D in the width direction is corrected, whereby a favorable winding shape can be obtained.

Next, the construction of the support arm 62 and the like which support the auxiliary edge restraining roller 56 will be explained. FIG. 8 is a partially plan view of FIG. 3, FIG. 9 is a left side view of FIG. 3, and FIG. 10 is a partially enlarged left side view of FIG. 3. In FIG. 10, only the auxiliary edge restraining roller 56 and its periphery are shown.

In FIG. 8, the support arm 62 is rotatably supported in the substantially horizontal direction by the upper arm 66 (see FIG. 3) via the roll bearing which is the rotational support point 64, at the base end portion 62B. FIG. 9 shows the state in which a track center 52K of the edge restraining roller 52 which presses the lower side of the tape roll 1′, and a track center 56K of the auxiliary edge restraining roller 56, which presses the upper side of the tape roll 1′ are displaced from each other.

Even in the state in which the track centers are displaced from each other by K, the support arm 62 rotates in the direction of the arrow A, or in the direction of the arrow B in FIG. 8 and FIG. 9, and thereby, the auxiliary edge restraining roller 56 moves to an appropriate position, whereby the protrusion D in the width direction is eliminated. Especially because the support arm 62 is supported rotatably in the substantially horizontal direction with the rotational support point 64 provided at the downstream side in the tape traveling direction as a center, the support arm 62 follows the position of the traveling magnetic tape 1, and is automatically settled down at the position where the load is least exerted, and thereby the protrusion D in the width direction can be eliminated. The aforementioned rotational support point 64 may have the construction except for a roll bearing if only the above-described function can be exhibited.

In the construction in which the positional control of the magnetic tape 1 in the width direction by the auxiliary edge restraining roller 56 explained above, it is preferable that the moving amount of the support arm 62 in the direction of the arrow A or in the direction of the arrow B is in the range of ±0.5 to 2.0 mm, for example, and it is preferable that the displacement amount K of the track centers is within the range of ±0.15 mm, for example, and it is preferable that the length 62L of the support arm 62 (the distance from the axis of the auxiliary edge restraining roller 56 to the axis of the rotational support point 64) is in the range of 20 to 150 mm, for example.

Next, a construction in which the vertical position of the auxiliary edge restraining roller 56 is controlled by the support arm 62 and the upper arm 66 will be explained. FIGS. 11A, 11B and 11C are partially enlarged side views showing positional relationship of the auxiliary edge restraining roller 56 and the tape roll 1′. In the drawings, FIG. 11A shows a state of start of winding of the magnetic tape 1, 11B shows the state in which winding of the magnetic tape 1 proceeds, and winding thickness of the magnetic tape 1 becomes such a value as is called “loading completion thickness d”, and FIG. 11C shows the state in which winding of the magnetic tape 1 further proceeds.

In the construction in FIGS. 11A, 11B and 11C, it is preferable to set a space between the narrowest portions of the inner surfaces of the flanges 56B of the auxiliary edge restraining roller 56 to be larger than the width of the magnetic tape 1 by 50 to 500 μm. By using such an auxiliary edge restraining roller 56, the position restraint in the width direction of the magnetic tape 1 to the winding hub 2 can be reliably performed, occurrence of a flaw of the magnetic tape 1 is restrained, and as a result, the quality of the pancake can be improved.

Namely, as shown in FIG. 11A, a narrowest space between inner surfaces of the flanges 56B (hereinafter, called “restraint width”) d1 is set to be larger than a width d0 of the magnetic tape 1 by 50 to 500 μm. Specifically, when the width d0 of the magnetic tape 1 is 12.650 mm, a width d2 of a shaft part 56A is set to be 12.700 mm, and the restraint width d1 is set to be 12.700 to 13.150 mm.

In the state from FIG. 11A to FIG. 11B, the flanges 56B and 56B of the auxiliary edge restraining roller 56 are freely running in contact with the winding hub 2. The position of the edge portion of the magnetic tape 1 is restrained by the inner surfaces of the flanges 56B and 56B. In this state, the magnetic tape 1 is not in contact with the shaft part 56A of the auxiliary edge restraining roller 56. In the state shown in FIG. 11B, a distance between the surface of the magnetic tape 1 at the outermost periphery of the tape roll 1′ and the surface of the shaft part 56A of the auxiliary edge restraining roller 56 is g, and the winding thickness of the magnetic tape 1 is at the value called “loading completion thickness d”.

From the state shown in FIG. 11B, the position of the auxiliary edge restraining roller 56 in the vertical direction is controlled so that the distance g is kept at a fixed value. Namely, as shown in FIG. 11C, in the state in which winding of the magnetic tape 1 further advances, the magnetic tape 1 and the shaft part 56A of the auxiliary edge restraining roller 56 are not in contact with each other.

As the construction which enables such an operation, a device which detects the outer diameter of the tape roll 1′ and a device which controls a position of the auxiliary edge restraining roller 56 are needed. As the device which detects the outer diameter of the tape roll 1′, a device which detects the rotational frequency of the winding hub 2 (tachometer or the like) is adopted (not shown). Namely, the traveling speed of the magnetic tape 1 is always constant, and the rotational frequency of the winding hub 2 changes in accordance with the outer diameter of the tape roll 1′. Accordingly, by detecting the rotational frequency of the winding hub 2, the outer diameter of the tape roll 1′ can be easily calculated.

Meanwhile, as the device which controls the position of the auxiliary edge restraining roller 56, the combination of the ball screw 70 and the servo motor 72, which is already described in accordance with FIG. 3, is adopted. Namely, the servo motor 72 is rotationally driven to control the position of the auxiliary edge restraining roller 56 in the vertical direction so that the distance g shown in FIGS. 11B and 11C is kept at a fixed value from the calculated outer diameter of the tape roll 1′. Such a control can be performed by a known device such as a microcomputer.

As the device which detects the outer diameter of the tape roll 1′, a construction other than the above, for example, the construction in which an air cylinder with a positional sensor is used as the biasing device of the lower arm 60 is used, and the outer diameter of the tape roll 1′ is obtained by detecting the rotating position of the lower arm 60 can be adopted. A construction in which a position sensor is attached to the auxiliary edge restraining roller 56 or the support arm 62 without obtaining the outer diameter of the tape roll 1′, and the distance g shown in FIGS. 11B and 11C is directly obtained can be adopted. Similarly, various kinds of known devices can be adopted as the device which controls the position of the auxiliary edge restraining roller 56.

Next, an operation of the manufacturing apparatus 10 of a pancake as constructed as above will be explained. First, in FIG. 1, the roll-shaped raw magnetic tape 20 wound around the hub 12 of the feeding device 11 is continuously drawn from the hub 12, and transferred to the cutting device 14. Subsequently, the raw magnetic tape 20 is cut into a plurality of magnetic tapes 1 by the cutting device 14, and transferred to the winding device 15, and wound around the winding hub 2. Thereby, for example, the raw magnetic tape 20 is cut into 100 to 500, and magnetic tapes 1 each of a specified width dimension (for example, 12.65 mm, 25.4 mm, 3.81 mm and the like) are manufactured.

In FIG. 3, the entry direction of the magnetic tape 1 into the tape roll 1′ is restrained by the position restraining roller 50 in the winding device 15. Next, the position of the magnetic tape 1 in the width direction is restrained by the edge restraining roller 52. Next, air between the magnetic tape 1 and the tape roll 1′ is pushed out by the pressing roller 54, and the winding shape is favorably restrained. The tape roll 1′ is supported by the auxiliary edge restraining roller 56 at the downstream by about 180 degrees of the tape roll 1′, and the width of the tape roll 1′ is gently restrained with predetermined looseness.

In this case, even if the track center 52K of the edge restraining roller 52 and the track center 56K of the auxiliary edge restraining roller 56 are in the state displaced by K as shown in FIG. 9, the auxiliary edge restraining roller 56 moves to a proper position as a result that the support arm 62 rotates, and thereby, a winding fault in which the magnetic tape 1 cannot be restrained by the flanges of the roller at the time of start of winding hardly occurs.

As the winding of the magnetic tape 1 advances and the outer diameter of the tape roll 1′ increases in this winding device 15, the lower arm 60 rotates around the support point 60B in the arrow direction in FIG. 3, and the edge restraining roller 52 and the pressing roller 54 keep pressing the tape roll 1′ with a proper pressing force by the rotation of the lower arm 60 and very small rotation of the support plate 58 around the support point 60A.

Similarly, as the outer diameter of the tape roll 1′ increases, the upper arm 66 rotates around the support point 66A in the arrow direction in FIG. 3, and the auxiliary edge restraining roller 56 keeps pressing the tape roll 1′ with a proper pressing force by the rotation of the upper arm 66.

More specifically, in the state from FIG. 11A of the start of winding of the magnetic tape 1 to FIG. 11B, there is no movement of the auxiliary edge restraining roller 56 in the vertical direction, as shown in FIGS. 11A to 11C already mentioned. The position of the edge portion of the magnetic tape 1 is restrained by the inner surfaces of the flanges 56B and 56B. In this state, the magnetic tape 1 is not in contact with the shaft part 56A of the auxiliary edge restraining roller 56.

In the state shown in FIG. 11B, the distance between the surface of the magnetic tape 1 at the outermost periphery of the tape roller 1′ and the surface of the shaft part 56A of the auxiliary edge restraining roller 56 is g. From this state, the position of the auxiliary edge restraining roller 56 in the vertical direction is controlled so that the distance g is kept at a fixed value by the control device already described. As shown in FIG. 11C, the magnetic tape 1 and the shaft part 56A of the auxiliary edge restraining roller 56 are not in contact with each other even in the state in which the winding of the magnetic tape 1 further advances. The position of the edge portion of the magnetic tape 1 is restrained by the inner surfaces of the flanges 56B and 56B. Thereby, the position restraint of the magnetic tape 1 in the width direction to the winding hub 2 can be reliably performed, and occurrence of a flaw of the magnetic tape 1 is restrained, as a result of which, the quality of the pancake can be improved.

The embodiment of the magnetic tape winding method and device and a pancake according to the present invention are explained thus far, but the present invention is not limited to the above-described embodiment, and various kinds of modes can be adopted.

For example, the magnetic tape is wound by the winding device 15 from the raw magnetic tape 20 via the cutting device 14 in this embodiment, but the mode in which slit treatment is previously performed and the magnetic tape is fed out in the state in which it already becomes the magnetic tape 1 of a predetermined width may be adopted.

The construction of the winding device 15 is not limited to this embodiment, but various kinds of constructions may be adopted. For example, the edge restraining roller 52 and the pressing roller 54 are supported by the plate 58 in this embodiment, but the construction in which they are individually supported by the lower arm 60 may be adopted.

Further, the example of this embodiment has the construction in which the upper arm 66 is rotated around the support point 66A in the vertical direction, but when there is the strong necessity of keeping the support arm 62 in the horizontal state, for example, the construction in which the upper arm is made a pantagraph mechanism and the support arm 62 is supported at the tip end portion rotatably in the horizontal direction can be adopted.

EXAMPLES Example 1

The winding test of the magnetic tape 1 was performed by using the winding device 15 of the construction shown in FIG. 3. As the magnetic tape 1, the mode in which the magnetic tape was fed in the state in which it was previously subjected to slit treatment and already became the magnetic tape 1 of the predetermined width was adopted. This magnetic tape 1 was 12.65 mm wide and 8.9 μm thick and was of a polyester base. As a pancake, the winding length of the magnetic tape 1 of 14,000 m is set. As the magnetic tape 1, those with various kinds of curvature amounts were prepared. As the curvature amount Δ, 0 to 6 mm were adopted with respect to L=1 m shown in FIG. 15B and FIG. 15C.

In the example, as the construction and the positional control in the vertical direction of the auxiliary edge restraining roller 56, the method explained in the “DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT” was adopted as it is.

Meanwhile, as a comparison example, the construction in which only the positional control method in the vertical direction of the auxiliary edge restraining roller 56 was made different was adopted. Namely, in the comparison example, the pressing device by the coil spring was used as the biasing device 66B of the upper arm 66 in place of the combination of the ball spring 70 and the servo motor 72. Accordingly, in the comparison example, the auxiliary edge restraining roller 56 was pressed by the tape roll 1′ with predetermined pressure, and the positional control of the auxiliary edge restraining roller 56 in the vertical direction was not made, whereby the magnetic tape 1 is in contact with the shaft part 56A of the auxiliary edge restraining roller 56.

In the example and the comparative example, the auxiliary edge restraining roller 56 having the construction explained according to FIG. 5 was adopted. The outer diameter of the roller 56A was 16 mm, the outer diameter of the straight portion 56D of the flange 52B was 26 mm, and the outermost diameter of the taper surface 56C was 30 mm.

The magnetic tape 1 was wound around the winding hub 2 with the traveling speed of the magnetic tape 1 set at 600 m/min, and the winding length where the winding defect did not occur was recorded as “winding OK length”. FIG. 12 is the graph showing the winding results of the example and the comparative example, the vertical axis is the winding OK length (unit: m) and the horizontal axis is a curvature amount A (unit: mm) of the magnetic tape 1.

In the example, in all the conditions of the curvature amounts Δ of 0 to 6 mm, the winding OK length was 14,000 m, and good products as the pancakes was able to be obtained in all the conditions.

On the other hand, in the comparative example, the winding OK length was 14,000 m in the condition of the curvature amounts Δ of 0 to 2 mm, but after the curvature amount Δ exceeded 2 mm, the winding OK length reduced extremely.

From the results in FIG. 12 shown above, it was confirmed that winding of the magnetic tape in the favorable winding shape at high speed was made possible by performing the positional control of the auxiliary edge restraining roller 56 in the vertical direction.

Example 2

The winding test of the magnetic tape 1 was performed by using the winding device 15 of the construction shown in FIG. 3. As the magnetic tape 1, the mode in which the magnetic tape was fed out from the state in which the magnetic tape was previously subjected to slit treatment and already became the magnetic tape 1 of the predetermined width. The magnetic tape 1 was of a polyester base of the width of 12.65 mm and the thickness of 8.9 μm. As the pancake, the winding length of the magnetic tape 1 was set at 14,000 m.

As in the example 1, the auxiliary edge restraining roller 56 having the construction explained according to FIG. 5 was adopted. The outer diameter of the roller 56A was 16 mm, the outer diameter of the straight portion 56D of the flange 52B was 26 mm, and the outermost diameter of the taper surface 56C was 30 mm.

Seven kinds of the auxiliary edge restraining rollers 56 the surface roughness Ra of which inner surfaces of the flanges 52B, namely the straight portions 52D and the taper surfaces 52C was changed from 0.05 to 0.25 μm were prepared, and were sequentially mounted to the winding device 15 by being replaced with one another, and the quality of the pancake in the surface roughness Ra was evaluated.

As the method for controlling the surface roughness Ra of the inner surface of the flange 52B, the surface roughness Ra was controlled by changing the buff condition (count or the like of the polishing cloth) of the flange 52B.

The evaluation result is shown in the table in FIG. 13. In the table, “abrasion pattern” which is the evaluation item is the presence and absence of the abrasion pattern which was recognized when the side surface of the pancake was visually observed. The case in which the abrasion pattern was not recognized was determined as the circle, and the case in which the abrasion pattern was recognized was determined as the cross. When the abrasion pattern was observed by the microscope, it was recognized that the damage occurred at the edge portion.

The “Edge damage” which is the evaluation item in the table in FIG. 13 is whether the problem such as a dropout occurs or not when the pancake was attached to the tape deck, and the case in which the problem did not occur was determined as the circle, and the case in which the problem occurred was determined as the cross.

According to the table in FIG. 13, in the condition in which the surface roughness Ra was 0.15 μm or less, both the items of the abrasion pattern and the edge damage were the determined as circles. On the other hand, in the condition in which the surface roughness exceeds 0.15 μm, neither of the abrasion pattern nor the edge damage was determined as a cross. Therefore, it can be said as preferable to control the surface roughness Ra of the inner surface of the flange 52B to be 0.15 μm or less. 

1. A tape winding method for winding a tape around a winding hub, comprising the steps of: placing an axis of the winding hub to be horizontal; restraining an entry direction of the tape into the winding hub by a first roller, which is provided at an upstream side in a tape traveling direction of the winding hub so that the axis of the winding hub and an axis of the first roller are substantially parallel with each other; restraining a position of the tape in a width direction by a second roller which contacts a tape roll formed by the tape being wound around the winding hub, and is provided so that the axis of the winding hub and an axis of the second roller are substantially parallel with each other; pressing the tape at an outermost periphery of the tape roll by a third roller provided so that the axis of the winding hub and an axis of the third roller are substantially parallel with each other; restraining a position of the tape in the width direction by a fourth roller with a flange which restrains the position of the tape in the width direction while contacting the tape roll, in a downstream side in a tape traveling direction of the third roller at the outermost periphery of the tape roll, and is provided so that the axis of the winding hub and an axis of the fourth roller are substantially parallel with each other; and winding the tape with a curvature amount of 6 mm or less per a tape length of 1 m around the winding hub.
 2. A tape winding method for winding a tape around a winding hub, comprising the steps of: placing an axis of the winding hub to be horizontal; restraining an entry direction of the tape into the winding hub by a first roller, which is provided at an upstream side in a tape traveling direction of the winding hub so that the axis of the winding hub and an axis of the first roller are substantially parallel with each other; restraining a position of the tape in the width direction by a second roller which contacts a tape roll formed by the tape being wound around the winding hub, and is provided so that the axis of the winding hub and an axis of the second roller are substantially parallel with each other; pressing the tape at an outermost periphery of the tape roll by a third roller provided so that the axis of the winding hub and an axis of the third roller are substantially parallel with each other; and controlling a distance of a fourth roller with respect to the tape roll so that a shaft part surface of the fourth roller does not contact the tape, in which the fourth roller is a roller which restrains the position of the tape in the width direction while contacting the tape roll at a downstream side in the tape traveling direction of the third roller at the outermost periphery of the tape roll, and is provided so that the axis of the winding hub and the axis of the fourth roller are substantially parallel with each other, and the fourth roller being constructed by a shaft part and flange parts disposed at both sides of the shaft part, having taper portions in which a space between the inner surfaces of the flange parts becomes larger toward the outer diameter direction from the inner diameter direction formed in the inner surfaces of the flange parts.
 3. The tape winding method according to claim 1, wherein the surface roughness Ra of the inner surface of the flange part of the fourth roller is 0.15 μm or less.
 4. The tape winding method according to claim 2, wherein the surface roughness Ra of the inner surface of the flange part of the fourth roller is 0.15 μm or less.
 5. The tape winding method according to claim 1, wherein a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm.
 6. The tape winding method according to claim 2, wherein a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm.
 7. The tape winding method according to claim 3, wherein a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm.
 8. The tape winding method according to claim 4, wherein a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm.
 9. A tape winding body manufactured by the tape winding method according to claim
 1. 10. A tape winding body manufactured by the tape winding method according to claim
 2. 11. A tape winding body manufactured by the tape winding method according to claim
 3. 12. A tape winding body manufactured by the tape winding method according to claim
 4. 13. A tape winding body manufactured by the tape winding method according to claim
 5. 14. A tape winding body manufactured by the tape winding method according to claim
 6. 15. A tape winding body manufactured by the tape winding method according to claim
 7. 16. A tape winding body manufactured by the tape winding method according to claim
 8. 17. A tape winding device for winding a tape around a winding hub, comprising: the winding hub disposed so that an axis is horizontal; a first roller provided at an upstream side in a tape traveling direction of the winding hub so that the axis of the winding hub and an axis of the first roller are substantially parallel with each other; a second roller which contacts a tape roll formed by the tape being wound around the winding hub and is provided so that the axis of the winding hub and an axis of the second roller are substantially parallel with each other; a third roller which presses the tape at an outermost periphery of the tape roll and is provided so that the axis of the winding hub and an axis of the third roller are substantially parallel with each other; a fourth roller which restrains a position of the tape in a width direction while contacting the tape roll at a downstream side in a tape traveling direction of the third roller at the outermost periphery of the tape roll and is provided so that the axis of the winding hub and an axis of the fourth roller are substantially parallel with each other, and the fourth roller being constructed by a shaft part and flange parts disposed at both sides of the shaft part, and having taper portions in which a space between inner surfaces of the flange parts becomes larger from an inner diameter direction to an outer diameter direction formed in the inner surfaces of the flange parts; and a control device which controls a distance of the fourth roller with respect to the tape roll so as to support the tape while preventing the contact of the tape to the shaft part surface.
 18. The tape winding device according to claim 17, wherein surface roughness Ra of the inner surface of the flange part of the fourth roller is 0.15 μm or less.
 19. The tape winding device according to claim 17, wherein a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm.
 20. The tape winding device according to claim 18, wherein a narrowest space between the inner surfaces of the flange parts of the fourth roller is set to be larger than the width of the tape by 50 μm to 500 μm. 